eat 流行于美国,既可指“吃”,也可指“喝”,但作“喝”讲时通常用于“喝”汤之类,如：
She is eating bread.她正在吃面包.
Do you like to eat soup?你喜欢喝汤吗?
have为普通用语,有吃喝的意思,在英国常用have代替drink,在美国常用eat代替have,与meal,dinner等表示三餐的词连用时多用have,而不用其他词,如：
He usually have lunch at home.他常在家里吃午饭.
She wants to have a cup of tea.她想喝杯茶.